Friday Night/Saturday Morning Freezing Rain Threat

[burrel2]

It's time to get this thread started.

The NAM is now in range of this event and it has my back yard at 29/20 at 1am Saturday morning with light rain falling. I'll take what little action I can get!

[mackerel_sky]

I'm at 30/19! Would be scary if we get some precip! Could wb down to 28 or so!

[FallsLake]

RAH's discussion on the threat (they're not too impressed for at least central NC):

"...Fri night through Sat night: The cold surface high will shift off
the mid Atlantic coast Fri evening with a warm front pushing
northward through S GA/E SC Fri night. This will result in a
residual cool stable surface-based pool over the NC Piedmont,
setting the stage for what may be our first taste of wintry weather
in the far NW forecast area. Warm advection precip will break out to
our N and W, through the Gulf States and Mid South through the S
Appalachians and mid Atlantic region, as weak perturbations tracking
to our NW and N contribute to lift. Both temps and dewpoints will be
very chilly within the in-situ stable pool over the Piedmont late
Fri night into early Sat, with resistance to horizontal dispersion
by the terrain and warm frontal zone, and to vertical dispersion via
the differential thermal advection, featuring a strong surge of
warm/moist air just a couple thousand feet off the ground, which
will serve to enhance the stability. GFS forecast soundings in the
Triad early Sat are more saturated below 700 mb than yesterday`s
runs showed, although moisture is limited above -5C, indicating the
likelihood of small hydrometeors and light precip amounts. Overall
forcing for ascent should remain focused closer to the mid level
wave path, to our W and N. Soundings also show that the lingering
stable layer below 950 mb is initially below freezing as the light
precip starts, topped by the strong warm air advection at and above
950 mb, favoring a chance of light rain/drizzle or freezing
rain/drizzle late Fri night into early Sat. Any such occurrence
would be of minimal consequence, given the light amounts and the
self-limiting latent heat release helped by the lack of near-surface
cold air advection. Precip should trend to just rain by mid morning
Sat as the column continues to warm, with all but the NW CWA likely
to be fully in the warm sector by sundown Sat, spreading everywhere
Sat night. ..."

[CAD_Wedge_NC]

42 minutes ago, FallsLake said:

RAH's discussion on the threat (they're not too impressed for at least central NC):

Soundings also show that the lingering
stable layer below 950 mb is initially below freezing as the light
precip starts, topped by the strong warm air advection at and above
950 mb, favoring a chance of light rain/drizzle or freezing
rain/drizzle late Fri night into early Sat. Any such occurrence
would be of minimal consequence, given the light amounts and the
self-limiting latent heat release helped by the lack of near-surface
cold air advection. Precip should trend to just rain by mid morning
Sat as the column continues to warm, with all but the NW CWA likely
to be fully in the warm sector by sundown Sat, spreading everywhere
Sat night. ..."

GSP not sold on anything more than a 1/10 of an inch.... Might get a "Freezing Rain Advisory" out of it.

LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
As of 300 PM Tuesday: Operational and ensemble guidance still in
good agreement on the upcoming forecast. Still looks like a short
lived light icing event develops Friday night and early Saturday.
Still can`t rule out some thunder, and possibly QLCS storms, south
of I-85 Sunday afternoon. Then below normal temps with a light,
generally cold rain through Tuesday.

The guidance is still progressive with the upper and surface
features Saturday. The very cold and dry air mass in place at the
start of the period will lead to freezing rain as moisture and
precip move in on increasing isentropic lift Friday night. The lift
continues Saturday morning before diminishing during the afternoon.
The upper and surface patterns are still unfavorable for a classical
damming event. Therefore, without a continuous feed of cold, dry
surface air, temps will be able to gradually warm through the day
Saturday changing the freezing rain to rain. Cannot rule out some
sleet at onset, but expect the bulk of the precip to be freezing
rain to rain. With the light QPF expected, any ice accretion will be
less than a tenth of an inch. Without the cold air locking into
place, melting should occur through the afternoon as well.

[mackerel_sky]

18z GFS says no Bueno on this threat! Very little moisture and late arrival!? So we have NAM, Euro,Ggem vs GFS! A grudge match! Lol

[VanillaDream]

Wow! If those dews over north ga verify and precip breaks out early could be a mess! Not looking likely though it seems.


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[oconeexman]

I'm starting to lean toward the lack of precipitation kind of like today. Would be a waste of some good cold dry air....although it's only tuesday so a little hope is left.

[oconeexman]

Although the 18z Nam looked pretty good to me for some action early saturday

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[cg2916]

[Brick Tamland]

Freezing rain can be really tricky around here. All it takes is more precip or it to last longer than expected to cause problems. I remember once getting stuck on a school bus and having a sheriff 's deputy take me home because of freezing rain that caused havoc on the roads when it was forecasted to just be a cold rain.

[Bhs1975]

41 minutes ago, Brick Tamland said:

Freezing rain can be really tricky around here. All it takes is more precip or it to last longer than expected to cause problems. I remember once getting stuck on a school bus and having a sheriff 's deputy take me home because of freezing rain that caused havoc on the roads when it was forecasted to just be a cold rain.

I remember a surprise 1/4 inch of icing a few years back in N Durham and Chapel Hill with temps around 30 which took down trees and limbs. An I-85 special of sorts, more like hwy 86/lLatta rd.

[mackerel_sky]

Good old KK on Fox21! Lol! Showing the Euro temps for this event! Has temps at 32 at 4am, up to 38 at 9am! Won't happen if precip starts

 

[Lookout]

The gfs is going to bust by 10 degrees at least sat morning..it's temps and dps are just insanely horrible.  I wouldnt be shocked if its 25 to 30 degrees too warm by sat afternoon. Good god the gfs is worthless since the upgrades with cad and evap cooling. 

To show you the absurdity...it raises dewpoints in many areas 30 degrees in 12 hours and of course temps rise after precip starts. Absolutely worthless. Nam is  much more realistic but even it might be a  bit too warm depending on how much precip falls. 

[Jon]

Just now, Lookout said:

The gfs is going to bust by 10 degrees at least sat morning..it's temps and dps are just insanely horrible.  I wouldnt be shocked if its 25 to 30 degrees too warm by sat afternoon. Good god the gfs is worthless since the upgrades with cad and evap cooling. 

To show you the absurdity...it raises dewpoints in many areas 30 degrees in 12 hours and of course temps rise after precip starts. Absolutely worthless. Nam is  much more realistic but even it might be a  bit too warm depending on how much precip falls. 

Yeah GFS is all alone, with NAM and Euro in the same camp, you have to discount it at this time. No way the wedge erodes that quickly.

[Lookout]

15 minutes ago, Jon said:

Yeah GFS is all alone, with NAM and Euro in the same camp, you have to discount it at this time. No way the wedge erodes that quickly.

To be clear im not saying it will be subfreezing all day but temps will be for a little whIle and i imagine temps will get stuck in the 30s most of the day..maybe 40 if it stays dry. But it showing temps rising to the upper 30s in nc by sunrise and low 60s here by 18z is worse than the old avn of the 90s. The gfs is just comical and totally worthless  here. 

 

[J.C.]

Just now, Lookout said:

To be clear im not saying it will be subfreezing all day but temps will be for a little whIle and i imagine temps will get stuck in the 30s most of the day..maybe 40 if it stays dry. But it showing low 60s here by 18z is worse than the old avn of the 90s. The gfs is just comical and totally worthless  here. 

 

Getting to 50 here near CAE is believable, but not 65, especially in Athens.  

[mackerel_sky]

Local news RPM in house model, has freezing rain over GSP area by 1 am Sat morning!!!

[AshevilleCityWx]

1 hour ago, mackerel_sky said:

Local news RPM in house model, has freezing rain over GSP area by 1 am Sat morning!!!

Doubt its reaching the ground tho at 1am. Too dry and light.

[FallsLake]

NAM-12km Simulated Radar at hour 72:

 

[whamby]

wow, that's one huge field of snow... 

[mackerel_sky]

19 minutes ago, FallsLake said:

NAM-12km Simulated Radar at hour 72:

 

Man, that looks juicy!

[mackerel_sky]

23 minutes ago, AshevilleCityWx said:

Doubt its reaching the ground tho at 1am. Too dry and light.

Even if it took 3 hours to saturate the atmosphere, 4-5 hours of light freezing rain and or drizzle, would be quite the nuisance! If NAM is close to right, it's almost down to CAE!

[rowjimmy73]

that sim radar is enough to make me set an alarm for sat early am to wake up my 2 and 4 yr olds. they have never seen snoow, sleet or freezing rain having been born in naples fl. been 7 long years since the wife and i have seen any winter weather. more excited by the 20/21 etc would love for her to end up with the entire week before christmas off due to weather. teaching in southside va rocks, cold, or wintery precip anticipated is enough to close school. 

would also be nice to get a little snow to play with the kids in before my hip surgery on 12/29..lets make it so!

 

[FallsLake]

Looks like surface temps would stay below freezing for the CAD areas until hour 78 (6z NAM). Then at hour 81 freezing temps are pushed back to areas around the Triad up into Virginia; then at hour 84 everybody is above freezing. Total freezing precip for the CAD areas still looks rather light; generally >.1 (for all areas), with  >.25 over parts of northern NC into southern Virginia.

 

[burrel2]

ARPEGE has the 32 line extending all the way to Atlanta,Augusta,Columbia at 7am Saturday morning. Even keeps a sliver of the upstate below 32 at 1pm on Saturday.

FWIW, I believe this model did slightly better with CAD events last winter at this lead time when compared to others.

[wncsnow]

1 hour ago, rowjimmy73 said:

that sim radar is enough to make me set an alarm for sat early am to wake up my 2 and 4 yr olds. they have never seen snoow, sleet or freezing rain having been born in naples fl. been 7 long years since the wife and i have seen any winter weather. more excited by the 20/21 etc would love for her to end up with the entire week before christmas off due to weather. teaching in southside va rocks, cold, or wintery precip anticipated is enough to close school. 

would also be nice to get a little snow to play with the kids in before my hip surgery on 12/29..lets make it so!

 

Good to see another Danvillean on the board! I think this situation all depends on how quickly the moisture gets in here, if it gets in early enough it will help lock in an in-situ wedge especially for the north areas of NC and VA, 

[Brick Tamland]

2 hours ago, FallsLake said:

Looks like surface temps would stay below freezing for the CAD areas until hour 78 (6z NAM). Then at hour 81 freezing temps are pushed back to areas around the Triad up into Virginia; then at hour 84 everybody is above freezing. Total freezing precip for the CAD areas still looks rather light; generally >.1 (for all areas), with  >.25 over parts of northern NC into southern Virginia.

Looks like we might be far enough north to see some frozen stuff.

And it would be funny if this end up being a bigger deal than next week's threat. 

 

[Brick Tamland]

NAM showing snow to ice.

 

[burrel2]

Check out the Dew points on the hi res NAM Friday afternoon.

[AshevilleCityWx]

3 hours ago, rowjimmy73 said:

that sim radar is enough to make me

would also be nice to get a little snow to play with the kids in before my hip surgery on 12/29..lets make it so!

NAM is notorious for its wet bias which is why people get burned by those sim radars every winter. Most just forget at the beginning.